High speed control circuit

ABSTRACT

A system providing an electrical pulse to mechanically drive a first piezoelectric element upon receipt of an electrical signal from a mechanically driven peizoelectric element. The system is adapted to provide a preselected frequency of from 16 to 120 impulses per second. The electrical signal from the second piezoelectric element is processed through a voltage comparator by comparison with a reference voltage and applied to a pulse stretcher circuit. The pulse stretcher circuit controls the gate of a silicon controlled rectifier which provides a signal from a power supply to an autotransformer that boosts the voltage from the power supply and applies the voltage to the second piezoelectric element. The pulse stretcher provides the additional function of preventing oscillation in the circuit.

Jayne Aug. 5, 1975 HXGH SPEED CONTROL CIRCUIT 3,431,436 3/1969 King307/240 x 3,583,226 6/1971 Codina [75] Inventor: Jayne Palnesvnev3,678,374 7/1972 Thompson .6 73/517 B Ohio [73] Assignee: The UnitedStates of America as Primary Eraminer-Malcolm F. Hubler represented bythe Secretary of the Attorney, Age/1!, or FirmR. S. Sciascia; HenryNavy, Washington, DC. Hansen [22] Filed: Oct. 23, 1973 21 A l N 406 459[57] ABSTRACT 1 pp A system providing an electrical pulse tomechanically Related US. Applicatio D drive a first piezoelectricelement upon receipt of an [63] Continuation-in-part f 5 N 749,521 J l26, electrical signal from a mechanically driven peizoelec- 1968. tricelement. The system is adapted to provide a preselected frequency offrom 16 to 120 impulses per sec- [52] U.S. Cl 328/69; 73/517 B; 310/84;end. The electrical signal from the second piezoelec- 73/DlG. 4; 307/252R tric element is processed through a voltage compara- [51] Int. CIR,GOlP 15/08; HO3K 17/74 tor by comparison with a reference voltage andap- [58] Field of Search 307/240, 252 R, 252 C; plied to a pulsestretcher circuit. The pulse stretcher 3lO/8.4; 73/514, 517 B, D10. 4;328/69 circuit controls the gate of a silicon controlled rectifier whichprovides a signal from a power supply to an [56] References Citedautotransformer that boosts the voltage from the UNITED STATES E T powersupply and applies the voltage to the second pi- 2 849 629 8/1958Kissinger 310/8 4 ezoelectric element. The pulse stretcher provides the3I4I34O 7/1964 i 73/515 additional function of preventing oscillation inthe cir- 3,2s5,074 11 1966 Elazar..... 73/1310. 4 3,325,7l8 6/1967McNulty. 307/240 X 3,343,073 10/1967 Ouclard 307/252 C 6 Clams 3 DramngF'gures IO IO4\ HIGH CELL VOLTAG E CIRCUIT BOUNCE REFERENCE RATE VOLTAGE101 CONTR- START BUTTO N VOLTAGE PULSE 2 SCR COMPARATOR STRETCHERCIRCUIT m 113 IOZ PATENTED AUG 5W5 SHEET HIGH SPEED CONTROL CIRCUITSTATEMENT OF GOVERNMENT INTEREST The invention described herein may bemanufactured and used by or for the Government of the United States ofAmerica for governmental purposes without the payment of any royaltiesthereon or therefor.

This is a continuation-in-part of application Ser. No. 749,521, filedJuly 26, I968.

BACKGROUND OF THE INVENTION The present invention generally relates toapparatus for maintaining an object in a bouncing state and moreparticularly to a system for sensing the location and providing thedrive for the object to place it and retain it in the bouncing state.

There are a variety of applications for objects kept in a bouncingstate. For example such objects can be used in the testing of theperformance of vehicles, such as a vehicle moving a straight horizontaltrack, a vehicle moving with 2 of freedom on a flat surface, or avehicle such as an airborne or space vehicle which, at different times,may move with 1, 2 or 3 of linear motion.

However, beyond the mere deriving of test data, such information in manyapplications is also of great importance in enabling ascertainment oftheposition and motion of a vehicle for purposes such as navigation,guidance and control. In one important group of applications it isimportant to be able to sense acceleration of an object by means ofapparatus carried with the object, as in the inertial guidance andcontrol of air and space vehicles.

A more extensive discussion of sensors for the latter type ofuse isdescribed in application Ser. No. 749,521 of Theodore D. Jayne entitledApparatus for Maintaining an Object in Bouncing Motion, and for Sensingand Indicating the Position and/or Motion Thereof, of which the presentinvention is a continuation-impart.

SUMMARY OF THE INVENTION Accordingly, it is a general purpose and objectof the invention to provide new and useful apparatus applicable tosystems for sensing and indicating the motion of an article such as avehicle. It is an additional object to provide a system for providing ahigh voltage output signal upon receipt of a low voltage input signal.Another object is that the system upon receipt of a plurality of inputsignals will not respond to other than the first signal unless suchsignals are sufficiently spaced in time. A further object is to preventoscillation of the system.

These and other objects are accomplished according to the presentinvention by providing an electrical circuit with a comparatorresponsive to a first signal for gating a switch for a predeterminedperiod of time. The switch gates an SCR for providing a signal to anautotransformer. The autotransformer then provides a high voltagesignal. The time elapsed from the receipt of the first signal to theoutput of the high voltage signal is approximately 2 usec. The systemalso is provided with a manual switch for providing the high voltageoutput signal.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an illustration partially inblock diagram of a system for maintaining an object in a bouncing state;FIG. 2 is a block diagram of the system of FIG. I; and FIG. 3 is aschematic representation of the block diagram of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. I there isshown a system employing the invention. A cell 10 comprises an upperpedestal I2 and an opposed lower pedestal 14, each of which is circularin horizontal cross-section and has an interior concave striking surfaceof generally spherical form as shown at 16 and 18, respectively. Upperpedestal 12 is mounted on the lower side of a relatively massive backingblock 20 while pedestal 14 is mounted on the upper surface of a firstpiezoelectric disc 27 having an electrode 28. A second piezoelectricdisc 22 having an electrode 26 is located beneath electrode 28. Discs 27and 22 can be made of lead zirconite titanite, such as that knowncommericially as clevite PZT-4. Discs 27 and 22 with electrodes 26 and28 are insulatedly mounted in a recess of mounting block 23. Block 23 isheld in place by frames 31 and 32. The pedestals l2 and 14 are held inposition by any appropriate mounting means, such as rods 24, which arefew enough in number and sufficiently spaced apart to enable a clearview through the cell from the sides at least at one angle and in somecases at several angles, so as to permit optical sensing ofthe positionof the ball within the cell 10 without interference from the rods. Thecell 10 may be supported on a grounded support frame 15.

A ball 30 of hard resilient material is given impetus to bounce back andforth between the striking surfaces i6 and 18 of the curved pedestals bypulsed actuation of the piezoelectric disc 22. Disc 22 is responsive tovoltage pulses applied to electrode 26 to cause the piezoelectric disc22 to expand along the direction between its major surfaces and thusimpart an upwardly directed mechanical impulse or shock wave to thelower side of pedestal 14 through disc 27. The wave is transmittedthrough the pedestal to the striking surface 18. By applying mechanicalimpulses to surface 18 when ball 30 is in contact with it, translationalkinetic energy is imparted to the ball 30 to make up for energy lost intransit of the ball 30 and thereby to maintain it in its bouncing state.

The voltage pulses for operating the piezoelectric element 22 aresupplied from high speed control circuitry 38. In order to produceoutput pulses from the high speed control circuitry at the proper timesto maintain bouncing of the ball, the times of impingement of the ballupon the lower pedestal 14 are sensed to produce control pulses fortriggering the control circuitry 38 into operation. In the presentexample, the initial contact of ball 30 against striking surface 18produces a shock wave in pedestal 14 which travels through it to theupper surface of piezoelectric disc 27, and the resultant instantaneouspulse of pressure between the opposite major surfaces of thepiezoelectric disc 27 induces an output voltage pulse between electrode28 and grounded pedestal 14 which is applied to the high speed drivercircuitry 38 via electrical lead 40 as a triggering impulse. In responseto this triggering impulse, the latter circuitry nearly instantaneouslyreturns a driving pulse along connecting lead 42, causing thepiezoelectric disc 22 to deliver an upward impulse to the ball while itis still in contact with the pedestal Referring now to FIG. 2 there isshown a block diagram of the high speed driver circuitry 38 and cellshown in FIG. 1. The driver circuitry 38 provides the function ofstarting and retaining an object such as a metal ball (FIG. 1) inbouncing motion. A start push button 101 is depressed to fire an SCRcircuit 102 which is provided with a signal from bounce rate controller103. The SCR circuit 102 conducts the signal from controller 103 to highvoltage circuit 104 which steps up the voltage of the signal and appliesthe signal to cell 10. Cell 10 on receipt of the signal from highvoltage circuit 103 gives the ball 30 a mechanical impulse to start inbouncing motion. The striking of the bottom of the cell 10 by the ball30 sends a signal to voltage comparator 111. A reference voltage 112,which may be ground. is also supplied to comparator 111. On the strikingof the bottom of the cell 10 by the ball, the signal from cell 10exceeds the reference voltage and the voltage comparator 111 provides apositive signal at its output. This positive signal is applied to pulsestretcher 113 which provides a signal to SCR circuit 102. SCR circuit102 functions as before and keeps the ball in bouncing motion.

FIG. 3 shows a schematic diagram of the system of FIG. 2. In the diagramthe cell 10 is shown with its lower metallic pedestal 14 grounded. Uppermetallic pedestal 12 together with lower pedestal 14 form the boundariesbetween which the ball 30 bounces. Thin piezoelectric crystal 27 onsensing a bounce on lower metallic pedestal 14 generates a signal thatis conducted to the remainder of the circuit by means of electrode 28and line 40. Line is connected to electrode 28 and conducts the signalgenerated by disc 27 to voltage comparator amplifier 130. Comparatorcompares the incoming signal on the positive terminal with its groundednegative terminal and upon sensing a positive incoming signal providesan output positive signal across a voltage divider comprised ofresistors 131 and 137. In addition the amplifier 130 has a zener diode133 connected to its input positive terminal for protec tion against anyexcessive transients that may occur.

The signal across divider 131, 137 is then applied to the cathode gateelectrode of silicon controlled switch through diode 138 which causesswitch 140 to fire. SCS 140 has its anode connected to a +12 VDC supplythrough a diode 141 and its gate anode connected to the same voltagesupply through a resistor 142. The cathode of SCS 140 is connected toground through a resistor 143. The cathode and cathode gate of SCS 140are connected by means of resistor 144. SCS 140 has its anode andcathode connected by means of the series connection of diode 145,capacitor 146 and parallel connected resistor 147 and capacitor 148.Capacitor 146 and the cathode of diode are connected to ground throughresistor 149. The SCS 140 and its associated components form pulsestretcher 113.

On firing, the anode of SCS 140 is raised to approxi mately 24 VDC whilethe anode gate receives the 12 VDC supply. Capacitors 146 and 148 thendischarge returning the SCS 140 anode to approximately 12 VDC andshutting off the SCS since by that time the signal on the cathode gateand any possible recurrences of the signal have been removed.

On manual operation of start button 101 or firing of SCS 140 a signal isapplied to the gate electrode of silicon controlled rectifier throughcapacitor 171 and the parallel combination of diode 172 and resistor173.

The anode of SCR 170 receives its voltage supply from bounce ratecontroller 103 which comprises an ac. voltage source 174, having oneside grounded. connected across adjustably tapped resistor 175 and fixedresistor 176. The position of the tap on resistor 175 determines thelevel of voltage applied to series connected rectifier diode 177 andresistor 178. A charging capacitor 179 is then connected.

The start push button 101 is connected between the 12 VDC supply and thecathode of SCS 140. A parallel connection of resistor 161 and capacitor162 connect one side of start button 101 to ground; the parallelconnection is located between resistor 160 and ground. A junction 181located between resistor 178 and capacitor 179 is connected to the anodeof SCR 170. Prior to firing of SCR 170 a rectifier voltage is formedacross the plates of capacitor 179. This voltage discharges uponconduction of SCR 170 so that shortly after firing the SCR 170 anodevoltage is unable to maintain firing and shuts off.

The SCR 170 on firing supplies a signal autotransformer 180 thatsupplies a high voltage signal to electrode 26 piezoelectric crystaltransducer 22 that converts the electrical energy into a mechanicalenergy and supplies an upward thrust to ball 30. A diode is connectedacross the primary coil portion of transformer 180 and preventsexcessive counter e.m.f. from developing across the primary coil anddamaging SCR 170.

In routine operzm of the system the ball 30 strikes the pedestal 14 sothat a voltage forms on disc 27. This voltage is applied to voltagecomparator amplifier 130. Comparator 130 on sensing the applied voltagesupplies a signal to SCS 140 that fires for a predetermined period oftime. SCS 140 on firing supplies a signal to the gate of SCR 170 thatcauses SCR 170 to fire for a short period of time until capacitor 179sufficiently discharges. SCR 170 supplies a signal to autotransformer180 that increases the voltage of the signal and supplies it topiezoelectric crystal 22. Crystal 22 supplies a mechanical impulse toball 30 to keep the ball 30 in motion. In addition a positive voltagecan be impressed on conductor 40 due to the force from trans ducer 22transferring mechanical motion to transducer 27. This signal howeverwill not cause oscillation in the circuit due to the firing time of SCS140 which will not shut off until this signal from transducer 27 hasdiminished.

It has therefore been shown a bounce drive system for use in keeping aball 30 in motion between pedestals 12 and 14 which the circuit 38 isresponsive to the ball 30 striking the pedestal 14. The circuit 38 hasthe capability to return a high voltage signal to transducer 22 causinga mechanical drive on the ball 30 prior to its leaving the surface ofthe pedestal. This system has been found to be applicable for use whenthe bounce rate is between 16 and 1 l5 bounces per second. The bouncecontact time is about 8 12sec. The bounce rate may be varied by varyingthe size of the cell or the voltage applied to transducer 22.

It will be understood that various changes in the details materials,steps and arrangements of parts, which have been herein described andillustrated in order to explain the nature of the invention, may be madeby those skilled in the art within the principle and scope of theinvention as expressed in the appended claims.

What is claimed is:

l. A high speed control circuit comprising:

a comparator circuit adapted to receive an electrical signal forproviding a first output signal upon said electrical signal exceeding apredetermined magnitude;

a pulse stretcher circuit connected to said comparator circuit forproviding a second output signal for a predetermined period of time uponreceipt of said first output signal;

a silicon controlled rectifier circuit connected to said pulse stretchercircuit for providing a third output signal upon receipt of said secondoutput signal;

a bounce rate controller circuit connected to said silicon controlledrectifier circuit for determining the magnitude and duration of saidthird output signal; and

a manual controller connected to said silicon controlled rectifiercircuit for providing an enabling signal to said silicon controlledrectifier circuit to enable said rectifier circuit to provide said thirdoutput signal.

2. A high speed control circuit according to claim 1 further comprising:

a high voltage circuit connected to said silicon controlled rectifiercircuit for increasing the voltage of said third output signal.

3. A high speed control circuit according to claim 2 wherein saidcomparator circuit further comprises:

a voltage comparator for comparing said electrical signal with areference signal and providing a positive output signal upon the voltageof said electrical signal exceeding said reference signal; and

a voltage divider circuit connected to said voltage comparator forproviding said first output signal upon receipt of said positive outputsignal.

4. A high speed control circuit according to claim 3 wherein said pulsestretcher circuit further comprises:

a voltage source; and

a silicon controlled switch connected to said voltage source and saidvoltage divider circuit for providing a conduction path for said voltagesource to form said second output signal for a predetermined period oftime upon receipt of said first output signal.

5. A high speed control circuit according to claim 4 wherein said bouncerate controller circuit further comprises:

an a.c. voltage source;

rectifier means connected to said a.c. voltage source for supplying apulsating dc. voltage; and

a capacitor connected to said rectifier means for receiving said do.pulsating voltage and connected to said silicon controlled rectifiercircuit.

6. A high speed control circuit according to claim 5 wherein said highvoltage circuit comprises an autotransformer having a portion thereofseries connected to said silicon controlled rectifier circuit.

1. A high speed control circuit comprising: a comparator circuit adaptedto receive an electrical signal for providing a first output signal uponsaid electrical signal exceeding a predetermined magnitude; a pulsestretcher circuit connected to said comparator circuit for providing asecond output signal for a predetermined period of time upon receipt ofsaid first output signal; a silicon controlled rectifier circuitconnected to said pulse stretcher circuit for providing a third outputsignal upon receipt of said second output signal; a bounce ratecontroller circuit connected to said silicon controlled rectifiercircuit for determining the mAgnitude and duration of said third outputsignal; and a manual controller connected to said silicon controlledrectifier circuit for providing an enabling signal to said siliconcontrolled rectifier circuit to enable said rectifier circuit to providesaid third output signal.
 2. A high speed control circuit according toclaim 1 further comprising: a high voltage circuit connected to saidsilicon controlled rectifier circuit for increasing the voltage of saidthird output signal.
 3. A high speed control circuit according to claim2 wherein said comparator circuit further comprises: a voltagecomparator for comparing said electrical signal with a reference signaland providing a positive output signal upon the voltage of saidelectrical signal exceeding said reference signal; and a voltage dividercircuit connected to said voltage comparator for providing said firstoutput signal upon receipt of said positive output signal.
 4. A highspeed control circuit according to claim 3 wherein said pulse stretchercircuit further comprises: a voltage source; and a silicon controlledswitch connected to said voltage source and said voltage divider circuitfor providing a conduction path for said voltage source to form saidsecond output signal for a predetermined period of time upon receipt ofsaid first output signal.
 5. A high speed control circuit according toclaim 4 wherein said bounce rate controller circuit further comprises:an a.c. voltage source; rectifier means connected to said a.c. voltagesource for supplying a pulsating d.c. voltage; and a capacitor connectedto said rectifier means for receiving said d.c. pulsating voltage andconnected to said silicon controlled rectifier circuit.
 6. A high speedcontrol circuit according to claim 5 wherein said high voltage circuitcomprises an autotransformer having a portion thereof series connectedto said silicon controlled rectifier circuit.